Learn · Updated 2026-09-29
The carbon footprint of leakage and non-revenue water
Every cubic metre lost to leakage carries the energy and chemicals it took to treat and pump it. How to estimate the tCO₂ embodied in real losses using treatment-process carbon factors.
Water utilities are among the largest energy users in most economies, and treated water that leaks away takes its embodied carbon with it. A carbon balance applies a unit carbon factor to each component of the water balance so leakage reduction can be expressed in tonnes of CO₂ as well as cubic metres and dollars.
Unit carbon by treatment process
| Treatment category | Typical unit carbon | Default uncertainty |
|---|---|---|
| Basic — no pumping, minimal chemicals | 30 gCO₂/m³ | ±5% |
| Traditional — multi-stage with chemicals | 300 gCO₂/m³ | ±10% |
| Desalination (RO) — clean energy | 3,200 gCO₂/m³ | ±15% |
| Desalination (RO) — fuel oil | 6,700 gCO₂/m³ | ±20% |
These defaults are derived from DEFRA (UK) factors and are intended for use in the absence of better data. If you have measured energy use per cubic metre and a grid emission factor, use your own figure and add any distribution pumping to the relevant source.
How the carbon balance is built
Each source is assigned a category. The volume-weighted average unit carbon across all sources is applied to every component of the water balance, from billed metered consumption to real losses. The uncertainty on each carbon figure combines the volume uncertainty and the carbon-factor uncertainty root-sum-square.
Why it changes the business case
For a system supplied by desalination, the carbon embodied in real losses can rival the operating-cost argument. A 10,000 m³/day leakage reduction on fuel-oil desalinated water avoids roughly 24,000 tCO₂ per year — a figure that speaks to regulators and boards in a way that litres per connection never will.
Put it into practice
Run your own water balance and see these indicators for your system — free, in about ten minutes.
Start a water balance